CDROM/AJ/V113/P0950
Kinematic Profiles of S0 Galaxies (Fisher 1997)
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Kinematic Profiles of S0 Galaxies
David Fisher
<1997, AJ, 113, 950>
=1997AJ....113..950F
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Abstract:
Stellar rotation curves, velocity dispersion profiles, and line-ofsight velocity distributions (LOSVD) as derived from absorption-lines
are presented for the major axes of 18 S0 and two elliptical
galaxies. Ionized gas rotation curves and dispersions were measured
from the [OIII] 5007 A emission line in the 9 S0 galaxies displaying
this feature. Minor-axis results are given for 14 of the S0 galaxies
and one of the ellipticals. A wide range of behaviors are observed in
the rotation and velocity dispersion profiles. These variations could
be the result of the superposition of stars and gas belonging to the
disks and bulges as well as the possible influences of bars, nuclear
disks, and warps. Deviations from a Gaussian LOSVD are found along the
major axes of all the galaxies in our sample. As parametrized by the
Gauss-Hermite series of orthogonal functions, asymmetric deviations are
always found in the inner regions of the S0 galaxies such that the
prograde wing of the LOSVD is steeper than the retrograde wing. This is
similar to the behavior observed in elliptical galaxies. However, at
larger radii these asymmetries can change their sign. We find that in 9
of the 18 S0 galaxies a high-speed tail to the LOSVD develops along the
major-axis beyond the central regions. In 3 of these 9 objects the
LOSVD asymmetries display a second change of sign with radius such that
a low-speed tail is again present and persists to our last measured
values. No correlations were found between the sizes of the stellar
velocity dispersion gradients and either central velocity dispersion,
absolute magnitude, disk-to-bulge ratio, Mg2 or Fe line strength
gradients. For the objects in our sample with edge-on orientations a
comparison between the minor-axis 'bulge' velocity dispersion gradients
and those found in elliptical galaxies indicates that the S0 bulges
display, on average, logarithmic gradients approximately 4 times
steeper than those found in normal luminous ellipticals. A number of
galaxies show particularly interesting features. For the LINER S0
galaxy NGC 3998 we find that the velocity dispersion profiles of both
the stars and gas rise sharply towards the center reaching nuclear
values of sigma ~ 320 km/s. Nuclear disks of rapidly rotating gas are
found in NGC 4350 and NGC 4762. A nuclear stellar disk is apparent in
the edge-on galaxy NGC 4111 and an extended disk of counterrotating gas
is observed in the barred S0 NGC 3941.
Description:
The data in tables 2, 3, and 4 have multiple lines per object, with
a header record that gives the object name and the position angle of
the velocity observations, followed by several lines of data measured
at various radii from the center, and with a single blank line
separating the observations of one object from the next.
File Summary:
------------------------------------------------------------------------------File Name
Lrecl
Records
Explanations
------------------------------------------------------------------------------table2.dat
38
1354
Stellar radial velocities and velocity
dispersions
table3.dat
38
498
Stellar Gauss-Hermite h3 and h4 terms
table4.dat
35
625
[OIII] 5007 A radial velocities and
velocity
dispersions
------------------------------------------------------------------------------byte-by-byte Description of file: table2.dat
------------------------------------------------------------------------------Bytes Format Units
Label
Explanations
----------------------------------------------------------------------------------- Header record ----1- 8
A8
--NGC
NGC number
9-12
4X
----Always ' PA='
13-15
I3
deg
PA
Position angle of observations
16
1X
----Blank
17-30
A14
--Comment
Comments
----- Data records ----1- 6
F6.2
arcsec
Radius
Radius measure from center of
galaxy
7-14
F8.2
km/s
RV
[]? Radial velocity
15-22
F8.2
km/s
e_RV
[]? Error in RV
23-30
F8.2
km/s
Sigma
[]? Velocity dispersion
31-38
F8.2
km/s
e_Sigma
[]? Error in Sigma
------------------------------------------------------------------------------byte-by-byte Description of file: table3.dat
------------------------------------------------------------------------------Bytes Format Units
Label
Explanations
----------------------------------------------------------------------------------- Header record ----1- 8
A8
--NGC
NGC number
9-12
4X
----Always ' PA='
13-15
I3
deg
PA
Position angle of observations
16
1X
----Blank
17-30
A14
--Comment
Comments
----- Data records -----
1- 6
F6.2
arcsec
Radius
Radius measure from center of
galaxy
7-14
F8.3
--h3
*Gaussian-Hermite h_3 parameter
15-22
F8.3
--e_h3
Error in h3
23-30
F8.3
--h4
*Gaussian-Hermite h_4 parameter
31-38
F8.3
--e_h4
Error in h4
------------------------------------------------------------------------------Notes for file: table3.dat
------------------------------------------------------------------------------h3, h4:
The velocity distribution is parametrised by the Gauss-Hermite series
of orthogonal functions yielding two measures of the deviations of
the line profile from a Gaussian: a parameter h_3 which measures
asymmetric deviations, and a parameter h_4 measuring symmetric
deviations.
------------------------------------------------------------------------------byte-by-byte Description of file: table4.dat
------------------------------------------------------------------------------Bytes Format Units
Label
Explanations
----------------------------------------------------------------------------------- Header record ----1- 8
A8
--NGC
NGC number
9-12
4X
----Always ' PA='
13-15
I3
deg
PA
Position angle of observations
16
1X
----Blank
17-30
A14
--Comment
Comments
----- Data records ----1- 5
F5.1
arcsec
Radius
Radius measure from center of
galaxy
6-14
F9.1
km/s
RV
Radial velocity
15-21
F7.1
km/s
e_RV
Error in RV
22-28
F7.1
km/s
Sigma
[]?=-99. Velocity dispersion
29-35
F7.1
km/s
e_Sigma
[]?=0.
Error in Sigma
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(End)
Lee Brotzman [ADS] 12Nov-1996